A Little Snow Fairy Sugar is the story of a young girl named Saga, and of a tiny fairy named Sugar.

Saga is organized and methodical beyond her years, always ready with a plan and schedule, or ready to make a plan or schedule. But as she goes about her daily business—working part-time at a little coffee shop, shopping with friends, playing piano at the local music store, and so on—her practical life takes an unexpected turn when she encounters a tiny snow fairy named Sugar. Season fairies make the weather of the world, though at the moment Sugar is only an apprentice in training.

Ordinarily, humans can't see or hear season fairies, and Saga quickly laments her extraordinary ability. Having a little being following her around and talking to her causes all sorts of problems for Saga, as Sugar is lively and curious, prone to unintentional mishaps. Sugar's antics are especially problematic when she accompanies Saga to school. The only relief Saga gets is when Sugar goes off with her best friends, fellow apprentice season fairies Salt and Pepper.

For apprentice season fairies to become full-fledged, they must search for "Twinkle" in the human world, though none of them know for certain—and indeed disagree on—what Twinkle even is. Their pursuit of Twinkle gets them into all sorts of trouble, at times requiring Saga's help to set things right, and at times annoying Saga to no end.

Through ups and downs, the characters' lives intertwine, and through many heartwarming moments they grow closer as friends. See the episode list for a more detailed outline of Saga and Sugar's charming adventures together.